The present invention relates to a device for mounting a switch or the like on a mounting plate. The switch normally comprises a housing with a housing top side supported on the back side of the mounting plate, a fastening protrusion including fastening means, as well as a plurality of resilient tongues, each having a locking protrusion. For mounting purposes the fastening protrusion and the resilient tongues are inserted from behind into an opening of the mounting plate. The locking protrusions thereby lock in place with the front edge of the opening. Furthermore, the device normally comprises a fastening element that can be mounted in a completing way from the front side of the mounting plate and cooperates with the fastening means of the fastening protrusion.
Such a device is e.g. known from DE 28 07 798 C2. The fastening protrusion is there configured as a sleeve. The resilient tongues are part of the sleeve wall and are each provided at their upper end with a locking protrusion. The sleeve is seated on the housing top side of the housing, which is here called a module carrier. For mounting purposes the sleeve is inserted with the locking protrusions from behind into an opening of the mounting plate, the locking protrusions locking in place with the upper edge of the opening. The module carrier is here for example supported by a resilient element on the back side of the mounting plate. Moreover, the sleeve comprises further locking protrusions that project beyond the upper edge of the mounting plate. The further locking protrusions serve to fix a cover.
DE 82 07 613 U1 reveals a further fastening device for a rotary switch or the like. The fastening protrusion of this fastening device is also designed as a sleeve comprising a plurality of locking protrusions, which are here called claws. The sleeve is inserted from behind through a bore of a mounting plate, which is designated as a carrier, the claws being engaged on the front side by resilience. It is here also suggested that the sleeve should comprise further claws that project beyond the upper rim of the carrier bore and serve to retain a front plate covering the carrier bore, or a decorative ring. The switch is clamped with a tension ring against the back side of the carrier.
A drawback of these devices known from the prior art is that a front plate mounted from the front or a mounted decorative ring or trim ring, also called a fastening element, must be made of a material with relatively high strength because this fastening element is held by locking protrusions that project beyond the upper rim of the mounting plate. Hence, the fastening element thereby forms a relatively large elevation for example of a control panel, which may be aesthetically undesirable. Moreover, this drawback may entail ergonomic deficiencies. Another drawback is that the tongues of the locking protrusions are relatively hard-sprung if a certain stability of the sleeve is to be ensured because the tongues themselves are part of the sleeve. A disassembly of the switch is therefore difficult and may also lead to irreparable damage in the case of correspondingly brittle materials. Likewise, the assembly of the switch may also turn out to be difficult, depending on the type of mounting plate.